The present invention relates to insect traps, and more particularly to devices for attracting, and trapping or killing, mosquitoes and other biting insects.
Biting insects, such as mosquitoes and flies, can be an annoying, serious problem in man""s domain. They interfere with work and spoil hours of leisure time. Their attacks on farm animals can cause loss of weight and decreased milk production. Worldwide, mosquito-borne diseases kill more people than any other single factor. Mosquitoes can be carriers of malaria, yellow fever, and dengue fever in humans. In the United States, mosquitoes spread several types of encephalitis, including the West Nile virus. They also transmit heart worms to cats and dogs.
People are not the primary blood hosts for mosquitoes and biting insects, especially in temperate climates. The major mosquito pests in the southeastern United States seem to prefer the host-odor of small herbivorous (vegetarian) mammals, such as rabbits, or birds. Mosquitoes that carry encephalitis seem to prefer avian (bird) blood hosts. These mosquitoes bite people when they get the chance, but they are better at tracking the scent of animals that are most abundant in their habitat.
People have tried a number of different methods to rid themselves of mosquitoes and other biting insects. One method that is often utilized is spraying or applying chemical insecticides. Although many chemicals work well to kill or repel mosquitoes, the chemicals often have a deleterious effect on the environment, including, but not limited to, killing beneficial insects. In addition, chemical insecticides are effective only for a limited amount of time, and thus must be continuously sprayed. Moreover, many types of mosquitoes and biting insects are capable of developing resistance to the chemical pesticides in a few generations (which may only take a few months for mosquitoes), and in the long run, that adaptation makes the species stronger.
Another method used to combat mosquitoes is bug zappers. In general, a bug zapper includes a fluorescent light source surrounded by an electrified grid. The theory behind these devices is that the mosquitoes are attracted to the light, and, upon flying to the light, will be electrocuted by the grid. In actuality, however, the bug zappers kill beneficial insects, and attract mosquitoes but does not kill them in significant numbers.
Citronella candles and smoking coils are often used to repel mosquitoes and other insects. However, research has shown that, in general, an individual must stand within the smoky plume of the citronella to be protected. This, of course, is not desirable. Moreover, even when standing in the plume, citronella is only partly effective in reducing the probability of a mosquito bite. Encouraging natural predation of insects by setting up bird or bat houses in the backyard has also been unsuccessful in reducing local mosquito populations.
Recently, significant research and effort have been expended to develop devices that attract and trap or kill mosquitoes. In general, these devices attempt to replicate the mosquito-attracting attributes of a typical blood host, such as a rabbit or a bird. Mosquitoes locate blood hosts by scent, sight and heat. From 100 feet away (30 meters) mosquitoes can smell a potential blood host""s scent, especially the carbon dioxide (CO2) the blood host exhales. Similarly, biting flies can smell their prey from 300 feet (100 meters) away. Because CO2 is present in the atmosphere (plants take in CO2 and give off oxygen), mosquitoes respond to higher-than-normal concentrations, especially when the CO2 is mixed with host-odor. They follow a blood host""s scent upwind, and can see a target at a distance of about 30 feet (10 meters). Devices that try to simulate a mosquito host thus may include, for example, a source of carbon dioxide, a source of octenol (an alcohol that is given off by mammalian blood hosts), and/or a heat source.
One such device is sold under the trademark xe2x80x9cMOSQUITO MAGNETxe2x80x9d and is described in U.S. Pat. No. 6,145,243 to Wigton et al. The MOSQUITO MAGNET apparatus is an insect trapping device that generates its own insect attractants of carbon dioxide (CO2), heat, and water vapor through catalytic conversion of a hydrocarbon fuel in a combustion chamber. The hot insect attractants generated in the combustion chamber are diluted and cooled to a temperature above ambient temperature and below about 115 degrees Fahrenheit (F) by mixing with air, and the mixture is exhausted downward through an exhaust tube. A counterflow of outside air is drawn into the trap though a suction tube that concentrically surrounds the exhaust tube. Biting insects are sucked into the suction tube and are captured in a porous, disposable bag connected to the other end of the suction tube. Additional chemical attractants may be used with the device to make the trap even more effective.
Although the MOSQUITO MAGNET device works well for its intended purpose, due to its high suggested retail price ($500 to $1300, depending upon the model), it is far out of reach of the ordinary consumer. Thus, few people would actually purchase the MOSQUITO MAGNET, even if they have a pressing need for mosquito control.
Another device that has been used in the past for trapping mosquitoes is the Center for Disease Control (CDC) light trap. The light trap includes a motor driven rotary fan to move attracted insects down into a holding container suspended beneath the trap, and a light source. More recently, the CDC light trap has been used with a source of carbon dioxide, usually dry ice. Dry ice produces carbon dioxide at a temperature below ambient, and works particularly well for attracting mosquitoes and other biting insects. Although a CDC light trap utilizing dry ice works well for its intended purpose, the handling and use of dry ice can be difficult and expensive.
The present invention provides an insect trap that utilizes a combustion chamber to produce carbon dioxide for an attractant. Combustion gasses from the combustion chamber are cooled in a conduit for the trap inlet. Thus, a single fan may be used for both drawing insects into the insect trap and for cooling the combustion chamber.
In accordance with an aspect of the present invention, combustion gasses, after being cooled by the flow of air through the conduit connected to the trap inlet, may be further cooled by a cooling system, such as a thermoelectric device. As such, the insect trap of the present invention may be used to produce carbon dioxide, via combustion, at temperatures at or below ambient temperature.
Other advantages will become apparent from the following detailed description when taken in conjunction with the drawings, in which: